Dear cafe, I discovered that stack/cabal is sensitive to permutations in the dependencies list. Is that desired behaviour and documented anywhere? #File stack.yaml resolver: lts-9.2 packages: - '.' extra-deps: [iCalendar-0.4.0.3,mime-0.4.0.2,wx-0.92.3.0,wxcore-0.92.3.0,wxc-0.92.3.0,wxdirect-0.92.3.0] flags: {} extra-package-dbs: [] system-ghc: false # In file myproject.cabal build-depends: base >= 4.7 && < 5 , HaXml >= 1.13.3 , iCalendar >= 0.3.7.3 , containers , time >= 1.6.0.1 , text , case-insensitive , xslx , xlsx-tabular , wx "stack build" generates the rather uninformative error message In the dependencies for myproject-0.2.1.0: xslx must match -any, but the stack configuration has no specified version # In file myproject.cabal build-depends: base >= 4.7 && < 5 , xlsx , xlsx-tabular , HaXml >= 1.13.3 , iCalendar >= 0.3.7.3 , containers , time >= 1.6.0.1 , text , case-insensitive , wx This version builds just fine. -- Olaf